Visual evoked potentials

A VEP is deemed to be present if it is recognizable, repeatable and falls within the normal range of implicit times expected for the child's age. The VEP is recognizable if the appropriate peaks are present. Repeatability is confirmed if, for repeated checkerboard presentations (for same-size checks), the peaks occur within 5 ms of each other. The waveform falls within normal limits if the reported peak (or peaks) appears within a predetermined range of the time expected for the patient's age.